Aseptic pump



y 1965 c. N. NELLIS ETAL 3,

ASEPTIC PUMP Flled May 25. 1964 2 Sheets-Sheet l CAM/P4 E6 M NH. ././5 vN'mRs G/NO MEACUR/AL/ A 7' TOR/VEY United States Patent 3,259,071ASEPTIC PUMP Charles N. Nellis and Gino Mercuriali, Cedar Rapids, Iowa,assignors to Cherry-Burrell Corporation, Cedar Rapids, Iowa, acorporation of Delaware Filed May 25, 1964, Ser. No. 369,898 2 Claims.(Cl. 10387) This invention relates to a pump and more particularly to acentrifugal-type pump that is suitable for use in aseptic processingsystems where a sterile product is being handled.

With a constantly increasing demand for products which are purer andwhich have better keeping qualities, more and more processors ofcomestible products are utilizing systems in which the product issterilized to destroy harmful bacteria and organisms that cause spoilageand shorten the shelf-life of the product. In order to preserve thesterility of a product, it must be handled after sterilization inequipment the design of which meets the highest sanitary standards.Thus, a demand has been created for pumps, fittings, valves, controlelements, etc. which are suitable for use in such systems without thefear of contaminating the sterilized product.

All processing systems require some means for moving the product throughthe system of equipment. Therefore, where used, a pump is perhaps themost important component of such a system but it is also probably one ofthe most difficult components to design aseptically because of itsmoving parts. There are, of course, various types of pumps used inprocessing systems today, but this invention is directed primarily to acentrifugal pump of the rotary-impeller type, this type being commonlyused in such systems.

It is therefore a principal object of this invention to provide a pumpsuitable for use in aseptic processing systems.

It is another object of the invention to provide an improved design of arotary impeller pump which will permit the handling of a product therebywithout the fear of contaminating the product even though leaks shoulddevelop in the seals used in the pump.

It is a further object of the invention to provide a rotaryimpeller-type pump in which all the seals are maintained in a sterileatmosphere by means of the introduction of a sterile gas in and aroundsaid seals.

It is a still further object of the invention to provide an aseptic pumpof the rotary impeller-type which is suitable for use in asepticprocessing systems and the design of which utilizes components ofexisting pumps to a maximum degree thereby standardizing a large numberof parts and simplifying the manufacture of the pump.

It is a still further object of the invention to provide an aseptic pumpthe design of which is relatively simple, easy to manufacture andtherefore relatively inexpensive even as compared to presently designedpumps not suitable for use in aseptic systems.

These and other objects of the invention will be readily apparent from aconsideration of the following description taken in connection with theaccompanying drawings in which:

FIG. 1 is a perspective view of the exterior of a pump of the type towhich the invention relates;

FIG. 2 is a side elevational view with the driven portion of the pump insection in order to show the details thereof; and

FIG. 3 is a transverse sectional View taken on the line 33 of FIG. 2.

Referring to the drawings, the exemplary embodiment of the inventionconsists of a motor suitably enclosed by a housing which is mounted onsupporting feet 12.

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The motor drives an impeller 14 inside of a volute-shaped pump housing16 which has a product inlet 18 formed in the center thereof and aproduct discharge duct 24 that discharges the product tangentially fromthe housing 16. On the pump side of the motor housing 10, there is abellshaped adaptor 22 which separates the motor housing 10 from pumphousing 16. The pump housing 16 is connected to the bell-shaped adaptor22 by means of a suitable clamping assembly 24 such as that shown inFIGS. 1 and 3. This permits the pump portion to be easily disconnectedfrom the motor portion for maintenance or repair. The back cover 26 ofthe pump has a radial flange 27 around its outer edge 28 that isinterposed between the adaptor 22 and the exterior pump housing 16, andthus, the back cover 26 is also held in place by the clamping assembly24. Two axially spaced 0 rings 29 provide seals between the outer edge28 of cover 26 and the pump housing 16.

Extending from the motor and through the center of the adaptor 22 is adrive shaft 30 which extends into a coupling 34 on the end of impellershaft 32. Key 36, fitted in suitable keyways in the coupling 34 and thedrive shaft 30, and a set screw 38 or other suitable means may be usedto secure the shaft 30 to the coupling 34.

The coupling 34 is welded or otherwise suitably affixed to the impellershaft 32. The opposite end of impeller shaft 32 extends into the productzone through a hub 40 in the center of cover 26 that has a relativelylarge central opening 42 through it. At the outermost end of shaft 32there is affixed the impeller 14 which is held in place by a nut 46threaded on the end of shaft 32. Other suitable locking means may alsobe used. Since lubricants generally are not used in a pump designed foraseptic or sanitary use, there is provided a ring-shaped carbon seal 50between the impeller 14 and an annular seat 52 against which the carbonseal 50 rotates. An 0 ring 54 is seated in a groove in the impellershaft 32 inside of the annular carbon seal 50. Another 0 ring 56 ispositioned 1n a groove formed in the outer periphery of the seal seat 52and provides a seal between seat 52 and the opening 42 in the hub 40 ofback cover 26.

A second carbon seal 58 is provided at the motor end of hub 40, the seal58 being positioned between the coupling 34 and a seat 60 similar toseat 52 that is fitted inside the opening 42 in hub 40. Suitable 0 rings62 and 64 provide seals between the canbon seal 58 and impeller shaft 32and the seat 60 and hub 40, respectively.

The seats 52 and 60 for the carbon seals 50 and 58 .are axiallyspaced-apart as shown in FIG. 2 and an open annular chamber 66 isthereby formed in opening 42 between the shaft 32 and the hub 40. A coilspring 68 or other resilient means is provided around shaft 32 inchamber 66 to bias the seats 52 and 60 apart against their respectiveseals.

The back cover 26 is somewhat dish-shaped and has two aligned radialribs 69 connecting hub 40 and the outer edge 28. Each rib 69 has a boss70 in the annular space between the hub 40 and the outer edge 28. Apassageway 72 extends partially through each of the bosses 70 along aline parallel to the axis of the impeller shaft 32. The passageways 72are each provided with a suitable fitting 74 for connection to a steamline 76. Radial passageways 78 in ribs 69 extend transversely ofpassageways 72 and interconnect them with the chamber 66 in hub 40. Thepassageways 78 also extend radially through the outer edge 28 of backcover 26 to an annular space 80 formed between edge 28 and pump housing16. Thus, steam or some other sterile gas can be introduced into one ofthe steam lines 74 and will flow through the passageways 72 and 78 bothto the chamber 66 and to the annular space 80. The steam will bedischarged through the other line 74. Thus, the seals provided by rings29 between the back cover 26 and the pump housing 16, the seals providedbetween the seats 52 and 60 by 0 rings 56 and 64, and the seals providedaround the impeller shaft 32 by 0 rings 54 and 62 will all beencompassed by the sterile gas. Therefore, if a leak should develop inany of these seals, the positive pressure of the sterile gas willusually prevent contaminating matter from being passed into the productzone, and even if foreign matter did leak through the seals, it would besterilized.

All the points of possible leakage from or into the product zone of thepump are sealed off with double mechanical seals as well as a steamseal. With the double seal arrangement, any leakage from the exteriorinto the product zone, or vice versa, is made very unlikely, and withthe addition of a sterile gas introduced into the space between each setof seals, contamination of the product is practically impossible. Thisarrangement meets and exceeds the highest known sanitary standards.

Although the invention has been described only in connection with acertain embodiment and a certain type of pump, it will be obvious tothose skilled in the art that various revisions and modifications can bemade to the disclosed structure without departing from the spirit andscope of the invention. It is the intention, however, that any suchrevisions and modifications be included within scope of the followingclaims.

We claim:

1. An aseptic pump comprising a housing, a back plate separable fromsaid housing and defining with said housing a product chamber, first andsecond seals extending continuously between the adjoining outer surfacesof said housing and back plate, said seals being spaced apart anddefining an annular space between them, a product inlet and a productoutlet in said housing, a rotatable impeller in said chamber to move theproduct through said inlet and discharge it through said outlet, powermeans to rotate said impeller, a shaft extending through said back plateand oper-atively interconnecting said power means and impeller, innerand outer concentric seals between said shaft and said back plate, saidseals being spaced apart axially with respect to said shaft to define anannular space around said shaft, means providing a first passageway insaid back .plate extending radially of said shaft and intercommunicatingsaid annular space around said shaft and said annular space between saidhousing and back plate, means providing a second passageway in said backplate extending radially of said shaft and intercommunicating the saidannular space around said shaft and the said annular space between saidhousing and said backplate, means providing an inlet to said firstpassageway between said annular spaces and adapted for connection to asource of sterilizing medium, and means providing an outlet from saidsecond passageway between said annular spaces for exhausting saidsterilizing medium from said space.

2. The aseptic pump of claim 1 in which said first and secondpassageways extend along radial lines from each other.

References Cited by the Examiner UNITED STATES PATENTS 1,666,013 4/ 1928Jackson 277-72 X 1,990,519 2/ 1935 Bigelow et a1 103-111 2,049,774 8/1936 Hoffman 103-111 2,555,492 6/ 1 Kidney 277-70 2,777,395 1/ 1957Disbrow 277-72 X 2,888,193 5/ 1959 Greenwald 103-111 3,084,943 4/ 1963Weis 277-72 X 3,191,545 6/1965 Funk 103-202 ROBERT M. WALKER, PrimaryExaminer.

1. AN ASEPTIC PUMP COMPRISING A HOUSING, A BACK PLATE SEPARABLE FROM SAID HOUSING AND DEFINING WITH SAID HOUSING A PRODUCT CHAMBER, FIRST AND SECOND SEALS EXTENDING CONTINUOUSLY BETWEEN THE ADJOINING OUTER SURFACES OF SAID HOUSING AND BACK PLATE, SAID SEALS BEING SPACED APART AND DEFINING AN ANNULAR SPACE BETWEEN THEM, A PRODUCT INLET AND A PRODUCT OUTLET IN SAID HOUSING, A ROTATABLE IMPELLER IN SAID CHAMBER TO MOVE THE PRODUCT THROUGH SAID INLET AND DISCHARGE IT THROUGH SAID OUTLET, POWER MEANS TO ROTATE SAID IMPELLER, A SHAFT EXTENDING THROUGH SAID BACK PLATE AND OPERATIVELY INTERCONNECTING SAID POWER MEANS AND IMPELLER, INNER AND OUTER CONCENTRIC SEALS BETWEEN SAID SHAFT AND SAID BACK PLATE, SAID SEALS BEING SPACED APART AXIALLY WITH RESPECT TO SAID SHAFT TO DEFINE AN ANNULAR SPACE AROUND SAID SHAFT, MEANS PROVIDING A FIRST PASSAGEWAY IN SAID BACK PLATE EXTENDING RADIALLY OF SAID SHAFT AND INTER- 